# Code Complexity Analyzer Measure cyclomatic and cognitive complexity across multiple programming languages > Canonical page: https://elysiatools.com/en/tools/code-complexity-analyzer - **Category:** Development - **Keywords:** complexity, static analysis, quality, cyclomatic, cognitive, code review ## Overview Analyze source code quality with cross-language complexity heuristics. **Checks included** - Cyclomatic complexity - Cognitive complexity - Long functions - Deep nesting - Duplicate code windows - Improvement suggestions ## Inputs - **Source Code** (textarea): Paste JavaScript, TypeScript, Python, Java, or Go source code here... - **Language** (select) - **Long Function Threshold** (number) - **Nesting Threshold** (number) - **Duplicate Window** (number) ## When to use - Preparing for code reviews to flag high-complexity functions that need simplification before merging - Refactoring legacy codebases to identify hotspots with excessive branching or nesting depth - Enforcing quality gates in development workflows to prevent complex code from entering production ## How it works - Paste your source code into the input field and select the programming language, or use auto-detect for supported languages - Configure thresholds for long function length, maximum nesting depth, and duplicate code window size to match your team's standards - The analyzer calculates cyclomatic complexity by counting branches and cognitive complexity by assessing human readability for each function - Receive a JSON report highlighting complexity hotspots, duplicate clusters, and specific improvement suggestions ## Use cases - Identifying refactoring candidates in legacy monoliths with undocumented complexity debt and untested branching logic - Automating code quality checks during pull request reviews to prevent technical debt accumulation in shared libraries - Educating development teams on complexity metrics by demonstrating concrete improvement opportunities in existing code ## Frequently asked questions ### What is cyclomatic complexity? Cyclomatic complexity measures the number of linearly independent paths through a function's source code by counting branches such as if statements, loops, and case clauses. Higher values indicate more test cases are required for full coverage. ### Which programming languages are supported? The analyzer supports JavaScript, TypeScript, Python, Java, and Go. You can manually select the language or use auto-detect to identify the syntax automatically. ### How does cognitive complexity differ from cyclomatic complexity? While cyclomatic complexity counts branches mathematically, cognitive complexity assesses how difficult code is for humans to understand, penalizing nested structures and logical jumps more heavily than simple sequential branches. ### What does the duplicate window setting control? The duplicate window defines the minimum number of consecutive tokens that must match to flag code as potentially duplicated. Lower values catch smaller similarities, while higher values identify only substantial copy-pasted blocks. ### Can I analyze multiple files or entire projects? Currently, the tool analyzes one code snippet at a time via paste input. 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